spu green stormwater infrastructure program & project update...don anderson, shanti colwell ......
TRANSCRIPT
SPU Green Stormwater
Infrastructure Program &
Project Update
Creeks, Drainage & Wastewater
Advisory Committee
October 8, 2014
Don Anderson, Shanti Colwell
• Green Infrastructure Program
• Active GSI Projects
Delridge NDS (design)
Ballard Natural Drainage System Phase 2 (design)
• GSI Program - Looking Ahead
GSI Program & Projects Agenda
Tries to make …function more
this… like this.
Green Stormwater Infrastructure
Too Much Runoff: flooding, sewer back-ups, overflows
Too Much Pollution: damage to local waterways
Stormwater Challenges
GSI Design Approaches
In July 2013, City Council
unanimously passed
Resolution 31549:
• GSI should be relied upon to
manage stormwater wherever
possible
• Target to manage 700MG
annually with GSI by 2025
• City Departments shall
collaborate with OSE to
produce Implementation
Strategy for meeting
new target
Policy + Program Development
Existing GSI
Projects in
Seattle
7
GSI Annual Report
seattle.gov/util/greeninfrastructure
Bioretention (Rain Garden)
Public Rights-of-Way Retrofits =
Natural Drainage Solutions (NDS)
GSI Policy + Program Development
•GSI Manuals Developed CIP Project procedural
expectations, for technical
design and community
engagement
•Pre-Vetted Concepts SDOT, SPU & DPD
•multidisciplinary team
Right of Way Context- Typical Elements
Public Rights-of-Way Retrofits
in Design or Construction
•Capitol Hill Water Quality Project
(Swale on Yale)
•Phase 1 completed construction
•KCWTD’s Barton Project
•Phase 1 completed construction
•Phase 2 construction 2015
•Venema NDS
•Construction start likely Oct/Nov 2014,
~10-month project
14
Venema Creek NDS
Seattle’s Drainage
Basins and How GSI
Helps
15
Active SPU GSI CIP Projects
Delridge NDS - Project Basics
Project Problem: CSO overflows into Longfellow Creek
Project Factors:
West Seattle, South Delridge Neighborhood
CSO Basins 168 & 169 Delridge Retrofit Projects Co-location of SDOT Greenway Historically underserved and
ethnically diverse community; Languages include: Spanish, Vietnamese, Somali
17
Entire Longfellow Creek Basin
Project Area
17th Avenue SW from SW Henderson to Kenyon
Streets, with side streets to the alley and further
(design-permitting) on Kenyon
Dropped Block from SG2 – Henderson to Barton,
future area contractions may occur
(blue area includes the current GSI project area, dashed green
lines include the SDOT Greenway project)
18
Purposes & Performance Goals
Reduce CSO frequency and volume into Longfellow Creek
Partner with SDOT in co-locating Greenway and GSI improvements to realize: shared benefits in the built environment (traffic calming & GSI)
efficiencies in design and outreach
enhanced community value
Bioretention cell bottom area of 5,890 SF and 17 blocks
220,000 gal/year CSO control volume reduction from Longfellow Creek; modeling estimates the annual reduction of 4.16 MG of flows to King County
The intent for all performance goals is to keep them scalable – geography could contract
19
GSI Within Existing Landscape Strips
Design Considerations
10’, 12’ strips
Parking – illegal and legal
Existing Trees
Concrete Panel Road
Utilities
Driveways, Sidewalks
Slopes < 5%
Adjacent Property Owner
Support
20
17th Avenue SW, Typical Landscape Strip
Other project constraints: regulatory deadline, performance goals for
gallons of runoff, informed consent with adjacent property owners,
neighborhood equity issues, O&M concerns, Greenway coordination
concerns.
Typical NDS
21
Example bioretention layout
Bioretention cells intermittent along
any block
Sited to avoid utilities, significant
trees, driveways
Curb bump-outs at some
intersections provide traffic calming
and room for GSI
22
Tree & Planting Design Process
Existing Tree Survey &
Assessment – in partnership
with SDOT
Context of existing public and
private trees
Consideration of GSI
Program approved trees and
plantings
Create a cohesive tree plan
across the project while
interjecting variety into the
existing monocultures
Appropriate species for
specific locations
constraints
23
Delridge NDS Sections
24
Delridge Landscape Palettes
25
Community Engagement
White Center CDA
community based
organizations –
ambassador model
SDOT Coordination
Surveys, three public
meetings, two walk-and-
talks, many door-to-door
discussions
Ongoing community
engagement continues
- August walk-and-talk,
Neighborhood
Associations 26
Neighborhood
Greenway Design
Elements
Greenways can include some combination of the following:
• 20 mph and wayfinding signs
• Stop signs
• Bicycle pavement markings
• Pavement repairs
• Speed humps
• Crossing improvements at
busy streets
• Bicycle parking
• Roadside Raingardens
Delridge NDS Project Timeline
28
Regulatory Deadline through our NPDES Permit – must give NTP by 10/31/2015
Permitting processes and timelines
Wet weather construction
Planting seasons
Ballard NDS 2015 –
Project Basics
Project Problem: Combined sewer overflows(CSO) into Salmon Bay
Project Factors:
Loyal Heights Neighborhood CSO Basins 150/151 & 152 Partnering with SDOT
programs Apply Lessons learned from
Ballard Phase 1 Combine with SPU CSO
storage facility in Ballard-Fremont-Wallingford area
29
Ballard NDS 2015 - Recommended Option
Potential NGW
(draft January
2014)
Ballard NDS 2015- Lessons Learned
31
Learned Looking Forward
TAKE YOUR TIME Allow sufficient time for project scoping, site selection, design, construction, and monitoring.
Build in time to respond to community and technical analysis
DO YOUR HOMEWORK
Conduct wet-weather soil testing and groundwater monitoring in advance and validate test results with outside experts.
Conduct more tests to assess soil conditions and measure how well water absorbs in areas
LISTEN TO THE COMMUNITY
Gather information from residents about what they know about existing conditions in their neighborhood. Engage residents early in siting
Identify locations that provide opportunities to improve community safety and livability.
Ballard NDS 2015 Public Engagement Community based
organizations (Loyal
Heights School &
Community Center)
ambassador model
Partner with SDOT
programs
Community Survey,
three public meetings,
two walk-and-talks,
many door-to-door
discussions
Ongoing community
engagement – Block
parties, neighborhood
association briefings,
additional door-to-door
discussions 32
Ballard NDS 2015 – Neighborhood Greenways (NGW)
• Safe, Calm residential
streets • Provides traffic slowing
benefits • Improves vehicle sightlines
and pedestrian crossing distances at key intersections
• Enhances streetscape aesthetics and continuity
• Contributes to tree canopy goals
33
Ballard NDS 2015 - SRTS
Safety improvements on
our streets including
Roadside Raingardens
ADA ramps
Curb bulbs
Marked crosswalks
34
SDOT Safe Routes to School (SRTS)
encourages physical activity through walking & bicycling
Ballard NDS 2015 Loyal Heights Elementary School
• Curb bulbs at end of blocks
where parking is illegal -
improves sightlines
• Curb bulbs and diversion
work trigger curb ramps at 4
intersections around school
to increase mobility and
safety of students on bikes
• Shorten crossing on 80th by
school
Ballard NDS 2015 Timeline
36
Options Analysis
Design
Construction
Public Engagement
F W S S F W S S F W S S F W S
2012-13 2014 2015 2016
= We are here
= Regulatory deadline 10-31-15
Ballard NDS 2015 – Performance Goals
Reduce CSO frequency and volume into Salmon Bay
Partner with SDOT programs and GSI improvements for: shared benefits in the built environment (traffic calming & GSI)
efficiencies in design and outreach
enhanced community value
Bioretention cell bottom area of 10,400 SF and 22 blocks
140,000 gal/year CSO control volume reduction from Salmon Bay; modeling estimates the annual reduction of 6.5 MG of flows to King County
The intent for all performance goals is to keep them scalable – geography could contract
37
Ballard NDS 2015 - Planting Palette
38
GSI Program – Looking Ahead
GSI Policy + Program Development
•Integrated Plan
•Developed neighborhood-driven GSI partnering option for EPA submittal
•Goal: Treat 80% AAV from 44 acres of impervious area with bioretention
(appx 4% of area shown below).
•Stormwater Code
•Updating on-site stormwater
management requirements
•LID code integration
•Review and update land-use
codes
GSI Policy + Program Development
GSI Retrofits:
Public Rights-
of-Way
Potential for
CSO reduction
or Integrated
Plan
In July 2013, City Council
unanimously passed
Resolution 31549:
• GSI should be relied upon to
manage stormwater wherever
possible
• Target to manage 700MG
annually with GSI by 2025
• City Departments shall
collaborate with OSE to
produce Implementation
Strategy for meeting
new target
Policy + Program Development
Questions?
City of Seattle
Seattle Public Utilities Ray Hoffman, Director
GSI Program Manager: Tracy Tackett, P.E.
Delridge NDS Project Manager: Don Anderson, P.E.
Ballard NDS Phase 2 Project Manager: Grace Manzano
www.seattle.gov/util/greeninfrastructure